LoD metadata info for 2nd level objects

[balazsdukai]

The cityfeaturemetadata and the presentlods don't have the correct counts with 2nd level object, such as BuildingPart.

Reproduce with multi-lod 3D BAG data:

cjio 3dbag_v210908_fd2cee53_5786.json subset --id "NL.IMBAG.Pand.0518100000285075-0" --id NL.IMBAG.Pand.0518100000285075 save --indent one.json

Then one.json contains:

"cityfeatureMetadata": {
	"Building": {
		"uniqueFeatureCount": 1,
		"aggregateFeatureCount": 1,
		"presentLoDs": {
			"0": 1
		},
		"BuildingParts": 1
	}
},
"presentLoDs": {
	"0": 1
},

This shows that there is only LoD0 in the file. However, the file still had LoD0, 1.2, 1.3, 2.2 for the Building and its BuildingPart.

[LaurensJN]

I encountered a similar problem that when city_model.update_metadata() is invoked, only LoD0 is added to the PresentLoDs. I think the root of the problem is in the following lines, where all Parts are deleted from the c_o_p list: https://github.com/cityjson/cjio/blob/d9b4636287563df8cb9cc6c868df407a21ed67c2/cjio/metadata.py#L99

Following, only the parent IDs are checked for LoDs, while the LoDs from children are never added to the parents' LoDs: https://github.com/cityjson/cjio/blob/d9b4636287563df8cb9cc6c868df407a21ed67c2/cjio/metadata.py#L114-L126